Oil well surveying device



Dec. 2o, 1932. G, H, BOWLUS `1,891,401

OIL WELL SURVEYING DEVICE Filed Sept. 30, 1930 GLENN H. BOWLUS Patented Dec. 20, 1932 GLENN H. BOWLUS, F ALHAMBRA, CALIFORNIA OIL WELL SURVEYING DEVICE Application filed vSeptember 30, 1930. Serial No. 485,568.

My invention pertains to the art of drilling deep wells, and specifically to the determina.- tion of the deviation of such wells from the vertical.

The object of my invention is to provide a means for determining such deviation which shall be free from the numerous errors inherent in the commonly used acid bottle method.

My improved device consists substantially of a metallic ball resting on a spherical segment which forms the bottom of a retaining cu p, this cup being sealed against the entrance of liquid and adapted in outer form to be lowered into or pumped down the drill pipe.

The cup is so formed that when the device A is set in a vertical position the ball will rest at the exact center of the bottom and will move away from this center as the device is 29 tilted, the extent of this movement being a measure of the deviation. t

In order to make this measurement permanent while the device is being withdrawn from the hole the cup is partially filled with some material which will remain liquid during the time required to run the device to the bottom of the drill pipe and will thereafter solidify.

In the accompanying drawing, Fig. 1 isa 39 longitudinal elevation of the device, partly in section. Fig. 2 is a cross-section of the longitudinally unsectioned device, taken on a lane through the ball 16 of Fig. 1. ferring to the drawing, Fig. 1, which illustrates in vertical section a preferred ernbodiment of my invention, 10 is a metallic body having such outer diameter as to slip easily into the drill pipe, 11 is a guide pipe or rod screwed into the lower end of the body 0 and 12 a flange or spider having the same outer measurement as the body, the guide and flange being adapted to hold the device in axial alignment with the drill pipe. A plug 13 may be inserted into a tapped hole in the insertion ofa rod to lift the disc from its position in the bottom of the cup after withdrawing the instrument.

The body Yis formed with a square shoulder 14 on which rests the disc 15 on which rests the ball 16.y The upper face of this disc is formed to a truly spherical curvature on a center which is exactly aligned with the axis of the device. The radius of curvature may be such that a deviation of say 6 from vertical will cause the ball to roll substantially to the edge of the curved surface, though any other curvature may be used if preferred, the accurac of the readingdiminishing asthe scope o the reading is increased. e

The disc 15 may be of glass, polishedon both faces and etched on its upper surface with concentric circles each o f which indi cates l? or a fraction of a degree of inclination. On such a disc the position of the ball may be observed frombelow and may tliusbe read without making measurement`s, Or the disc may be of polished .metal or quartz in which case the position of the ball must -be measured vby instruments applied from above.

The disc is held on the shoulder by a soft gasket ring 17 retained by a compression ring 18 and the upperend vof the cup is closed by a screw plug 19. The edges of the disc engage the approximate'middle of the inner edge of the gasket ring 17, which may be made of rubber. When screw plug 19 is tightened, compression ring 18 expandsthe gasket ring 17 by pressing upon it and forces its inner edge into tight contact with the disc.

It is important that all the joints be nonleaking under high pressure, as the intrusion of water or mud will prevent the functioning of the device.

Before insertiny the instrument into the Y drill pi e a suita le fluid is introduced on to of t e disc, in quantity sutlicient to form a ayer over the entire curved surface. The nature of this fluid must be such that it will maintain its fluid condition while the device is being passed to the bottom of the'drill pipe, so as to permit the ball to roll to the low polnt of the curvature after the instrument has come to rest, and such that it will solidify a short time thereafter, as say within ten minutes after being poured in. When the well is known to be cold, that is if the temperature at the bottom is not over 100 F., a readily fusiblev material such as paraffin may be used, the device being heated to say 210 just prior to insertion and the residual heat maintaining `day of Sept., 1930.

the paraffin in fusion for several minutes. Low melting point metallic alloys may also be used, but must be so selected as not to further alloy with the surface of the dise. For higher temperatures materials which set slowly, such as dental cements, may be used. Any setting material must be ground to a state of impalpable fineness and mixed to a completely fluid condition in order not to interfere with the free movement of the ball lOVQI the ClllVGd SllffilCQ.

This device is used by insert-ing it into the drill pipe just prior to coming out and pumping mud fluid behind it until a rise in pressure indicates that it has been stopped by the bit, after which it is allowed to stand for a few minutes to ensure the solidification of the luid. The drill string is then run out in the usual manner, the instrument removed from the last joint, the cap removed and the position of the ball on the disc measured.

It will be understood that While I have shown an illustrative embodiment of my invention in some detail I do not restrictmyself to the structure shown, the scope of my invention being limited solely by the following claim.

I claim as my invention n an instrument for measuring the inclination of a drill pipe: a transparent disc having a spherically curved upper surface and concentric rings marked on said surface, a ball of a high specific gravity selid resting thereon, and a shallow coating of a solidifiable material on that surface of said dise which carries the said ball.

In witness that I Claim the foregoing I have hereunto subscribed my name this 25th GLENN H. BOWLUS. 

